How Many Englishmen Does It Take To Change A Light Bulb?

Today’s blog post is brought to you by TCP new addition, Chris Roach. Chris is originally from the United Kingdom and recently joined TCP’s marketing team. Upon his arrival to TCP, Chris had to quickly get up to speed on all things lighting. As a newbie to the lighting world, Chris will be posting a series of posts to help get others that are new to lighting up to speed. Enjoy today’s post!

Hailing from the United Kingdom and new to the world of lighting, I didn’t realize that light bulbs came in such a variety.

Being British, I am accustomed to the bayonet style mount. This style typically consists of a base with two radial pins which is pushed, and then twisted, into a matching L-shaped slot. The Bayonet mount is the standard in many of the Commonwealth countries including Australia, India, Ireland, New Zealand and many African Nations.

However, this style is not commonly found in the American market. Here in the United States the Edison screw (E) base is king. As the name suggests, this base type was developed by Thomas Edison. This threaded base simply screws into a matching socket. Most will have a right-hand threading that is screwed in clockwise, although some lamps and fittings are purposely made with a left-hand thread to deter theft.

These Edison screw bases come in a range of different dimensions; from the small Candelabra (E12) base seen on many decorative bulbs, to the large Mogul (E39) base used on street lights. However, the most common screw base that you are likely to find around your house is the Medium sized (E26) base (so called because it measures 26mm in diameter). To further complicate matters Europe prefers to go with E11, E40 and E27 sizes respectively.

The Typical E26 Base On A TCP CFL

LED With An E12 Base

Finally, there is the G or Bi-pin base family. These base types are found on smaller lamps (especially halogen and MR16), and on many fluorescent lights. The bi-pin base was invented by Canadian inventor Reginald Fessenden for the 1893 World’s Fair in Chicago. The base types are usually listed by the letter G followed by a number. This number represents the distance between the pins in mm.

As a consumer in the USA, it seems that the main decision regarding sockets used in the home would be identifying whether you need a medium screw (E26) which is the most common style, or the smaller candelabra screw (E12) commonly seen on the smaller decorative bulbs found in a chandelier for example.

So now armed with this knowledge, I can confidently go about the job of changing a light bulb, be it in London, England, or in London, Ohio.